I had my two back molars on the top left side of my mouth filled about 3 weeks ago and after a few days, everything was fine. No pain, nothing. But a few days ago, I realized that every time I drink hot, cold, and sometimes even room temperatured liquids therebisna sharp almost piercing pain that lasts for a few seconds. (More so with the cold than hot or room temperatured) It doesn't hurt to bite down but it does hurt to actually chew something on that side. Even when I take a deep breath through my mouth, the cold air hurts the tooth. The pain feels like the liquid or the air is literally going inside my tooth and releasing that sharp pain. I made an appointment to see my dentist and he said thw nerve might be exposed, what does the mean for me? What kind of procedure needs to be done? Or what do you think is wrong?